Brain Rules for Aging Well. John Medina
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with hormones such as catecholamines and glucocorticoids, released in response to stress), and “social exchanges” (to describe interactivity). I’m going to use the word “relationships” more often to keep things friendly. But if you have social interactions that are positive—whether deep or momentary, with one person or dozens—benefits accrue.
What about the digital world? Does the social interaction have to be in person? Researchers realized long ago that the Internet might provide a perfect way for socially isolated, mobility-challenged seniors to interact with others. The rise of video chats created a terrific experimental test bed. Could people increasingly tethered to home still get a brain lift?
The answer, welcome as a Rothko retrospective, was again yes. One experiment involved people eighty years and older, measuring a baseline for executive function skills and an aspect of language ability that’s related to executive function. Executive function (EF) is a behavioral gearbox mostly housed in the prefrontal cortex, an important region located right behind your forehead. EF includes cognitive control (such as the ability to shift attentional states), emotional regulation (such as the ability to manage your anger), and short-term memory. The researchers got baseline EF scores, then installed a video-chat program for each person and proceeded to hold conversations with the octogenarians, averaging thirty minutes per day for six weeks. Four and a half months later, their brains were retested.
Researchers observed large improvements in both executive function and language skills. The scores leapfrogged over controls who spoke for thirty minutes by phone only. This is consistent with other data suggesting that the better you simulate actual human contact, the richer the social experience becomes. Video chat is not perfect, but for those without the option of regular human contact, it’s a godsend.
These findings are worthy of a J. D. Power award for senior citizen customer satisfaction. Which means you should get out your social calendar, iron your best clothes, and go run a board meeting. Or visit a museum. The answer to the question “Does socialization really decrease the rate of cognitive decline?” is a robust and hearty “Yes.”
How exactly does the buoyant power of socialization work? Two main ways: it reduces stress, which helps maintain not only the body’s general health but specific aspects of the immune system, and it’s a workout for the brain.
More parties, less flu
The more positive social interactions you have, the lighter your allostatic load becomes, as neuroendocrinologist Bruce McEwen would put it. He’s the researcher who came up with the concept of “allostatic load.” Allostatic load is the aggregate effect of stress on your body’s capability, including brain capability, through time. The more stress you encounter, the bigger the load (and the greater the damage). Consider stress metaphorically: the stresses in life are oceanic waves, and your body is a cliff. The more waves that crash onto the cliff, the greater the erosion, and the more severe the total effect. Allostatic load is the measure of your body’s deterioration, in response to the lifelong waves of stress you experience.
Less stress is important particularly for the immune system. The immune system naturally becomes compromised as you age, but the more stressed you are, the greater risk you run of weakening parts of the immune system. We even know why. One critical arm of the immune system involves a group of cellular warriors known as T-cells. These cells play critical roles in wound healing (like when you get a cut) and recovering from infectious diseases (like when you get colds and flus). Stress hormones like cortisol—at the high levels you experience when you’re in a bad marriage or otherwise chronically stressed—actually kill T-cells. Your wounds heal at a rate 40 percent slower if you’re in a high-hostility marriage than in a low-hostility one. And you get more colds. Says elderly-care expert Gary Skole: “Those elderly folks who get out and interact and spend more time with people during cold/flu season actually get fewer colds and illnesses than those who spend most of their time alone.”
These data serve to underscore the growing link in the scientific literature between positive interactions, stress reduction, and longer life. No doubt Karl and Elizabeth are right now busy nodding their heads. And Karl’s dad is probably rolling around in his grave.
A workout for your brain
One of the reasons why social interactions are so good for you is that they take so much energy to maintain, consistently giving your brain a bona fide workout. Case in point is a clip from the movie When Harry Met Sally. The scene is where Sally (Meg Ryan) asks Harry (Billy Crystal) to come over for some major-league consolation: Sally’s ex has decided to marry someone else. Through tears and sobs and gobs of tissues, Sally tells Harry, “All this time, I’ve been saying that he didn’t want to get married. But the truth is, he didn’t want to marry me.” Harry, bless him, attempts his best lifeboat impression, although by now Sally is nearly drowning in a cocktail of saltwater and snot. “I’m difficult!” she blubbers. Harry counters thoughtfully: “Challenging.” Sally sobs, “I’m too structured, I’m completely closed off!” Harry shrugs: “But in a good way.”
With unexpurgated grief in Sally’s case and measured restraint for Harry, the amount of energy the two exude in this delightful scene is extraordinary. It illustrates something scientists have known for years: flesh-and-blood friendships take work. And that’s because social interactions take work. And by work, I mean in a biochemical, energy-expending kind of way. Some researchers believe social interactions are the most complex, energy-intensive jobs your brain can consciously perform. Every time it intermingles at a cocktail party or consoles a friend, the organ experiences the cognitive equivalent of an aerobic workout.
Says Chelsea Wald, writing in Nature magazine: “[Researchers] suspect that the cognitively demanding act of socializing can actually build up the brain—like exercising builds up muscles. This ‘brain reserve’ may then act as a buffer against functional loss, even in the face of conditions such as Alzheimer’s disease.”
Suppose you were the scientist hypothesizing that social interactions are cognitive calisthenics. You might predict that the more social interactions you have, the more you exercise the brain regions responsible for those interactions. You might further hypothesize that the neural tissue will become bigger and stronger or more active as a result. You might guess there would even be bleed-through effects, given that the job descriptions of most brain regions are hopelessly intertwined with those of other regions, all moonlighting to produce a broad array of functions. From cell to behavior, you can measure whether growth is occurring.
And scientists have. Though the data are largely correlative, growth is exactly what they find.
Let me pause for a moment to define a few terms: social activities, social networks, and social cognitions. Researchers define these terms much as the public does, especially if that public uses words like “neurological substrates.” Social activities are the actual experiences you have with others, whether going out on a boat or going out on a date. Social networks are the number of people with whom you willingly have those experiences. Close friends and family generally populate these activities. Social cognitions are the psychological (and by implication, neurological) substrates you use to interact with others when socializing.
On to the studies showing that the brain is being exercised.
The more social relationships you maintain, the bigger the gray matter volume in specific regions of your frontal lobe. Which means that relationships are to the frontal lobe what milk shakes are to your waistline. The frontal lobe is the large region right behind your eyes, running to the middle of your head (where a headband would sit). This region is associated with a cognitive gadget called mentalizing, or Theory of Mind. Mentalizing is the ability to discern the mental states of others, particularly their motivations and intentions. It’s as close to mind reading as your brain will ever get. Mentalizing abilities play a powerful role in establishing and maintaining social relationships, as you can imagine.
The frontal lobe is also responsible for helping you predict the consequences of your own actions. It helps you suppress socially inappropriate behaviors and even make comparative decisions. For many reasons, these are important regions to keep fat and happy.